Biophysical studies of motions and interactions of membrane proteins
Date
2011
Authors
Winter, Peter William, author
Barisas, B. George, advisor
Roess, Deborah A., advisor
Crans, Debbie C., committee member
Bamburg, James R., committee member
Journal Title
Journal ISSN
Volume Title
Abstract
We have utilized a variety of biophysical techniques to quantitatively examine the motions and interactions of transmembrane proteins on living cells at the single-molecule level. These include both widefield and confocal optical microscopic methods such as single particle tracking, Förster resonance energy transfer and ratiometric imaging of phase-sensitive probes of lipid order, together with spectroscopic fluctuation methods such as fluorescence correlation spectroscopy and photon counting histogram analysis. Our studies indicate that; 1. Luteinizing hormone receptors on CHO cells and KGN human granulosa cells exhibit restricted lateral diffusion and increased self-association after exposure to human chorianic gonadotropin; 2. In addition to insulin receptor and IGF1 receptor homodimers, rat basophilic leukemia 2H3 cells express significant levels of insulin receptor-IGF1 receptor heterodimers; 3. Clustering of insulin receptors after exposure to insulin on rat basophilic leukemia 2H3 cells is affected by disruption of actin-filaments but not by extraction of membrane cholesterol; 4. Chromium Picolinate and Bis(maltolato)oxovandium(IV) both restrict the lateral diffusion of insulin receptors on rat basophilic leukemia cells and; 5. Individual FcE receptors on rat basophilic leukemia cells exhibit orientation fluctuations on millisecond timescales.